Laser needle provides painless injections

BY NICOLETTE
EMMINO

It’s safe to say that nobody enjoys
the painful prick of injections at the doctor’s office.
Soon, we may not have to dread vaccinations thanks to a new type of
needle, providing an almost painless experience.

A new laser-based system developed by Jack Yoh
and his team at Seoul National University in South Korea, uses an
erbium-doped yttrium aluminum garnet (Er:YAG) laser to inject a
small amount of medicine with the perfect amount of force under the
skin. This type of laser is one commonly used by dermatologists for
facial procedures.

Image via ucf.edu

So, how does it work?

The device comprises three parts: a laser, a
small adapter containing the drug, and a chamber containing water.
The water is the driving force propelling the drug. A flexible
membrane separates the water from the liquid drug. When
it’s time for vaccination, a laser pulse is emitted,
lasting about 250 millionths of a second. The pulse creates a vapor
bubble that causes the flexible membrane to bend and the drug to
release through a nozzle that is just 150 millionths of a meter
wide.

The image shows the system being tested on
skin-like gel. The jet punctures a hole in the skin and at a lower
pressure the drug is injected. (Image via Jack Yoh, Optics
Letters)

The team has recently conducted tests on guinea
pigs proving that the new needle can penetrate up to several
millimeters beneath the skin’s surface with no tissue
damage. The team aims to inject the drugs into the epidermal layer
where there are no nerve endings. The design of the jet (its narrow
and quick qualities) ensures the pain free experience.

Yoh and his team experimented with different
laser wavelengths in order to arrive at the current model. They
found that by using a laser wavelength of 2,940 nanometers, the
vapor bubble needed to propel the drug will form correctly without
causing any shock waves like they had seen in previous studies.

Other methods have been tested including
mechanical injecting devices, but these derivatives are not as
accurate since the drug dosage can’t be controlled.

“Control via laser power is the major
advancement over other devices,” said Yoh in a statement
to the Optical Society of America.

This pain-free laser-based injector is not just
a fantasy. Yoh is currently working with companies to produce
low-cost versions for clinical-use for application in the near
future.■